Module 1 Lesson 5 - 5

Lesson Summary

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In this lesson, you have explored the following focusing questions:

• What are the structures and functions of the neuron? How do they support communication?
• What are the components of the reflex arc?

You have examined the dendrites that receive information and pass it to the cell body. The cell body performs life functions and passes the information to the axon. Then, the axon passes information to its terminal. The axon has many specialized parts. The Schwann cell is a special support cell that wraps around the axon and produces an insulating fatty layer called myelin. The insulation of myelin increases the rate of signal conduction. The nodes of Ranvier also increase the rate of signal conduction.

Whether you withdrew your hand from a hot stove or, as a goalie, you stopped a fast-moving puck, the response involved three types of neurons. The sensory neuron is able to receive stimuli from the sensory receptor and pass this information to the interneuron in the grey matter of the spinal cord. The interneuron is structured so that it can send nerve impulses to the brain for further processing, or it can stimulate a third type of neuron the motor neuron. Motor neurons stimulate effectors (muscles and glands). A motor neuron also initiates a quick involuntary response called a reflex. The reflex behaviour gives protection to the body and enables survival.